<!DOCTYPE html>
<html>
<head>
    <meta charset='utf-8'/>
    <title></title>
    <meta name='viewport' content='initial-scale=1,maximum-scale=1,user-scalable=no'/>
    <script src='../assets/mapbox-gl-dev.js'></script>
    <link href='../assets/mapbox-gl.css' rel='stylesheet'/>
    <style>
        body {
            margin: 0;
            padding: 0;
        }

        #map {
            position: absolute;
            top: 0;
            bottom: 0;
            width: 100%;
        }
    </style>
</head>
<body>

<style>
    .map-overlay {
        font: bold 12px/20px 'Helvetica Neue', Arial, Helvetica, sans-serif;
        position: absolute;
        width: 25%;
        top: 0;
        left: 0;
        padding: 10px;
    }

    .map-overlay .map-overlay-inner {
        background-color: #fff;
        box-shadow: 0 1px 2px rgba(0, 0, 0, 0.20);
        border-radius: 3px;
        padding: 10px;
        margin-bottom: 10px;
    }

    .map-overlay label {
        display: block;
        margin: 0 0 10px;
    }

    .map-overlay input {
        background-color: transparent;
        display: inline-block;
        width: 100%;
        position: relative;
        margin: 0;
        cursor: ew-resize;
    }
</style>

<div id='map'></div>

<div class='map-overlay top'>
    <div class='map-overlay-inner'>
        <label for="slider">Layer opacity: <span id='slider-value'>100%</span></label>
        <input id='slider' type='range' min='0' max='100' step='0' value='100'/>
    </div>
</div>

<script>
    mapboxgl.accessToken = 'pk.eyJ1IjoibWFvcmV5IiwiYSI6ImNqNWhrenIwcDFvbXUyd3I2bTJxYzZ4em8ifQ.KHZIehQuWW9AsMaGtATdwA';
    var map = new mapboxgl.Map({
        container: 'map',
        style: 'mapbox://styles/mapbox/light-v9',
        center: [-87.6321, 41.8362],
        minZoom: 9.5,
        maxZoom: 13,
        zoom: 9.5
    });

    var slider = document.getElementById('slider');
    var sliderValue = document.getElementById('slider-value');

    map.on('load', function () {

        map.addLayer({
            "id": "chicago",
            "source": {
                "type": "raster",
                "url": "mapbox://mapbox.u8yyzaor"
            },
            "type": "raster"
        });

        slider.addEventListener('input', function (e) {
            // Adjust the layers opacity. layer here is arbitrary - this could
            // be another layer name found in your style or a custom layer
            // added on the fly using `addSource`.
            map.setPaintProperty('chicago', 'raster-opacity', parseInt(e.target.value, 10) / 100);

            // Value indicator
            sliderValue.textContent = e.target.value + '%';
        });
    });
</script>

</body>
</html>